Service provider login number changing

Hi there,i have a friends computer that keeps changing the login number to conect to the internet.
when he goes to conect to the net a diferent number is isn the dial up box to what is supose to be there...i have been working on systems for about 16 to 18 years as a hobby but dont know all the answers.
i have changed his number back to what it is supose to be but when i go to log in it disconects and comes up with will redial in 60 secs then that screen dissapears..when i click on it again to log in there is a totaly different number in there like ( 0037254111951) and even this number changes...the normal login number is 087303030...i have tryed nod 32,hijack this,spybot search and destroy and trend micros homecall to see if i can get rid of what ever is causing this...i know it is some kind of bug or trojan..but i cant seem to get ride of it.
Can anyone help with a program that might detect where the problem is.
I have even deleted his conection and created a new one and it works the first time but then when i go to log in the second time it is back up with those numbers again.

go to here and download 'Hijack This!' self installer. Save it to the desktop or other suitable place. DO NOT just press run from the website Double click on the file and it will install to C:\program files\hijackthis and create an entry in the start menu and an optional shortcut on desktop.
Click on the entry in start menu or on the desktop to run HijackThis
Click the "Scan" button, when the scan is finished the scan button will become "Save Log" click that and save the log.
Go to where you saved the log and click on "Edit > Select All" then click on "Edit > Copy" then Paste the log back here in a reply.
It will possibly show issues deserving our attention, but most of what it lists will be harmless or even required,
so do NOT fix anything yet.
Someone here will be happy to help you analyze the results.

Download WinPFind3U.exe to your Desktop and double-click on it to extract the files. It will create a folder named WinPFind3u on your desktop.

Open the WinPFind3u folder and double-click on WinPFind3U.exe to start the program.

In the Processes group click ALL

In the Win32 Services group click ALL

In the Driver Services group click Non-Microsoft

In the Registry group click Non-Microsoft

In the Files Created Within group click 60 days Make sure Non-Microsoft only is CHECKED

In the Files Modified Within group select 60 days Make sure Non-Microsoft only is CHECKED

In the File String Search group select Non-Microsoft

In the additional scans section, please select only these

Reg - Desktop Components

Reg - Disabled MS Config Items

Reg - Safeboot Options

File - Additional Folder Scans

[*]Now click the Run Scan button on the toolbar.
[*]The program will be scanning huge amounts of data so depending on your system it could take a long time to complete. Let it run unhindered until it finishes.
[*]When the scan is complete Notepad will open with the report file loaded in it.
[*]Save that notepad file

Use the Reply button and attach the notepad file here . I will review it when it comes in.

hi there..tried to send you a pm and it says im not able to do that yet?...at any rate the number he is supose to use and one of the numbers that come up are both in my origanal post..the 087303030 is the normal number..the big long 0037254111951 is one of the numbers that takes it's place.